System and devices including valves coupled to electric devices and methods of making, using, and operating the same

ABSTRACT

Systems, methods, and devices are disclosed, including a compressor having a piston and a valve assembly. In some embodiments, the valve assembly includes a check valve having a valve member, a magnet coupled to the valve member, and an electrical conductor near the magnet. The check valve may be configured to change state in response to a change in fluid pressure. The compressor may also have an electric device coupled to the electrical conductor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and benefit of PCT PatentApplication No. PCT/US2009/045864, entitled “System and DevicesIncluding Valves Coupled to Electric Devices and Methods of Making,Using, and Operating the Same,” filed Jun. 1, 2009, which is hereinincorporated by reference in its entirety, and which claims priority toand benefit of U.S. Provisional Patent Application No. 61/076,544,entitled “System and Devices Including Valves Coupled to ElectricDevices and Methods of Making, Using, and Operating the Same”, filed onJun. 27, 2008, which is herein incorporated by reference in itsentirety.

BACKGROUND

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present invention,which are described or claimed below. This discussion is believed to behelpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentinvention. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

In a variety of systems, fluids are compressed and conveyed by acompressor, and often, these compressors include valves that open andclose during a compression cycle. Typically, one set valves open as thecompressor draws a low-pressure fluid into a compression chamber, andafter the fluid is compressed, another set of valves open to allow thecompressed fluid to exit the compressor. During each compression cycle,each set of valves both opens and closes.

The movement of the valves is a form of energy that is typically wasted.In most conventional systems, when a moving valve reaches the end of itstravel, it impacts some structure, and the impact dissipates valve'skinetic energy. Typically, the impact converts the kinetic energy toheat and sound that are radiated away from the system. This wastedenergy can be substantial. In some systems, hundreds of valves open andclose several times per second. Over the course of a year of continuousoperation, these systems waste a large amount of energy.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein:

FIG. 1 is a perspective view of a reciprocating compressor including anexemplary energy-scavenging system in accordance with one embodiment ofthe present invention;

FIG. 2 is an axial, cross-section view of the exemplary compressor ofFIG. 1, illustrating internal components of the compressor in accordancewith one embodiment of the present invention;

FIG. 3 is a cross-section view of an exemplary poppet valve assembly inaccordance with one embodiment of the present invention;

FIG. 4 is a perspective view of another exemplary poppet-valve assemblyin accordance with one embodiment of the present invention;

FIG. 5 is a front-elevation view of an exemplary cage of thepoppet-valve assembly of FIG. 4 in accordance with one embodiment of thepresent invention;

FIG. 6 is a front-elevation view of an exemplary poppet-cage assembly ofthe poppet-valve assembly of FIG. 4, in which the exemplary poppet-cageassembly includes several components disposed within the cage of FIG. 5in accordance with one embodiment of the present invention;

FIG. 7 is a partial, cross-section view of the exemplary valve assemblyof FIG. 4, illustrating various internal components of the valveassembly, including a poppet in a closed position in accordance with oneembodiment of the present invention;

FIG. 8 is a partial, cross-section view of the exemplary valve assemblyillustrated in FIG. 7, depicting the poppet in an open position inaccordance with one embodiment of the present invention;

FIG. 9 is a diagram of an exemplary energy-scavenging system inaccordance with one embodiment of the present invention;

FIG. 10 is a circuit diagram of a portion of the energy-scavengingsystem of FIG. 9 in accordance with one embodiment of the presentinvention;

FIG. 11 is diagram illustrating a passive-damping system in accordancewith one embodiment of the present invention;

FIG. 12 is a flowchart illustrating an exemplary energy-scavengingprocess in accordance with one embodiment of the present invention;

FIG. 13 is a representation of an actuation system in accordance withone embodiment of the present invention;

FIG. 14 is a flowchart illustrating an actuation process in accordancewith one embodiment of the present invention;

FIG. 15 is a partial, cross-section view of a second example of a poppetassembly in accordance with one embodiment of the present invention;

FIG. 16 is a side view of another example of a poppet assembly inaccordance with one embodiment of the present invention; and

FIG. 17 is a cross-section view of the poppet assembly of FIG. 16 inaccordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

One or more specific embodiments of the present invention will bedescribed below. These described embodiments are only exemplary of thepresent invention. Additionally, in an effort to provide a concisedescription of these exemplary embodiments, all features of an actualimplementation may not be described in the specification. It should beappreciated that in the development of any such actual implementation,as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

When introducing elements of various embodiments of the presentinvention, the articles “a,” “an,” “the,” and “said” and the like areintended to mean that there are one or more of the elements. The terms“comprising,” “including,” “having,” and the like are intended to beinclusive and mean that there may be additional elements other than thelisted elements. Moreover, the use of “top,” “bottom,” “above,” “below,”and variations of these terms is made for convenience, but does notrequire any particular orientation of the components.

FIG. 1 illustrates an example of a compressor 10 configured to generateor consume electrical energy. In the illustrated embodiment, thecompressor 10 includes electric devices 11 and 11′ that, as explainedbelow, in some embodiments, converts kinetic energy to electricalenergy. The compressor 10 includes a variety of moving parts, and assome of these components move, the electric devices 11 and 11′ bothscavenge electrical energy and dampens the component's movement. In someembodiments, the electrical devices 11 and 11′ may dampen thecomponent's movement by dissipating the resulting electrical energyrather than scavenging the electrical energy. Further, in someembodiments described below, the electric devices 11 and 11′ deliverelectrical power that generates a force counteracting movement of somecomponents or assisting movement of some components. This may delay oradvance the time at which valve members open or close, therebymodulating the compressor's capacity. Multiple embodiments of theelectric devices 11 and 11′ are described below, after describing thecompressor 10 in greater detail.

In this embodiment, the compressor 10 includes a pair of compressioncylinders 12 coupled to a frame 14. As discussed in greater detailbelow, a variety of internal components may be disposed within thecylinders 12 and the frame 14 to compress fluids within the cylinders12. In one embodiment, the compressor 10 may be used to compress naturalgas. However, in other embodiments, the compressor 10 may be configuredor utilized to compress other fluids, such as air or other gases. Amechanical power source or driver 16, such as an engine or an electricmotor, may be coupled to the compressor 10 to provide mechanical powerto the various internal components and to compress the fluid within thecylinders 12. To facilitate access to such internal components, as maybe desired for diagnostic or maintenance purposes, openings in the frame14 may be provided and selectively accessed via removable coversdisposed over the openings.

Further, the exemplary cylinders 12 include capped recesses 18configured to receive valve assemblies, such as valve assembly 20. Whileonly a single valve assembly 20 is illustrated, it will be appreciatedthat, in various embodiments, additional valve assemblies are includedwithin some or all of the other capped recesses 18. It will also beappreciated that the cylinders 12 may include internal fluid conduitsbetween the recesses 18 and the valve assemblies 20 to facilitate flowof a fluid into and out of the cylinders 12 through such valveassemblies. Additionally, various installation components, such as cagesor fasteners, may be employed to facilitate mounting of the valveassemblies 20 within the recesses 18.

In this embodiment, each of the valve assemblies 20 is connected to theelectric device 11 (or 11′) through one of four phase paths 21, 23, 25,and 27 (or the phase paths 21′, 23′, 25′, or 27′). Each phase path 21,23, 25, and 27 connects to a group of valve assemblies 29, 31, 33, and35, and each phase path 21′, 23′, 25′, and 27′ connects to a group ofvalve assemblies 29′, 31′, 33′, and 35′.

Each group 29, 31, 33, and 35 and 29′, 31′, 33′, and 35′ includes valveassemblies 20 that move generally simultaneously during the cycle of thecompressor 10, which is described below with reference to FIG. 2. Forinstance, the valve assemblies 20 in groups 31, 31′, 35, and 35′ aredischarge valve assemblies that open in response to an increase in fluidpressure arising from the piston (which is described below withreference to FIG. 2) moving toward their respective sides of thecylinders 12. The valve assemblies 20 in groups 29, 29′, 33, and 33′ maybe suction valves assemblies that open in response to a decrease influid pressure arising from the piston moving away from their respectivesides of the cylinders 12.

The phase paths 21, 23, 25, 27, 21′, 23′, 25′, and 27′ may connectgroups of valve assemblies 20 that open and close at generally the sametime. For instance, the phase paths 21 and 21′ connect to valveassemblies 20 in groups 35 or 35′; the phase paths 23 and 23′ connect tovalve assemblies 20 in groups 33 or 33′; the phase paths 25 and 25′connect to valve assemblies 20 in groups 31 or 31′; and the phase paths27 and 27′ connect to valve assemblies 20 in groups 29 or 29′.

These valve assemblies 20 are described below with reference to FIGS.4-8. The valve assemblies 20 that open during a compression stroke arereferred to as “discharge valves,” and the valve assemblies that openduring a suction stroke are referred to as “suction valves.” Thus, thepresent embodiment includes four phase paths 21, 23, 25, and 27 (or 21′,23′, 25′, or 27′) for each piston and one phase path 21, 23, 25, and 27(or 21′, 23′, 25′, or 27′) for each type of valve assembly, suction ordischarge, associated with each piston.

In the illustrated embodiment, the groups of valve assemblies 29 and 33are disposed on a top half of the cylinders 12, and the groups of valveassemblies 31 and 35 are disposed on a bottom half of the cylinders 12.In other embodiments, though, the groups may by intermingled around thecylinders 12.

Although the exemplary compressor 10 is illustrated as a two-throwreciprocating compressor, other compressor configurations may alsoemploy and benefit from the presently disclosed techniques. Forinstance, in other embodiments, the compressor 10 may include adifferent number of cylinder throws, such as a single-throw compressor,a four-throw compressor, a six-throw compressor, a couple-freereciprocating compressor, a screw compressor, or the like. Further,other variations are also envisaged, including variations in the lengthof stroke, the operating speed, and the size, to name but a few.

A cross-section view of the exemplary compressor 10 is provided in FIG.2, which illustrates a number of exemplary internal components of thecompressor of FIG. 1. In the presently illustrated embodiment, the frame14 of the exemplary compressor 10 includes a hollow central body orhousing 22 that generally defines an interior volume 24 in which variousinternal components may be received, such as a crankshaft 26. In oneembodiment, the central body 22 may have a generally curved orcylindrical shape. It should be noted, however, that the central body 22may have other shapes or configurations in full accordance with thepresent techniques.

In operation, the driver 16 rotates the crankshaft 26 supported withinthe interior volume 24 of the frame 14. In one embodiment, thecrankshaft 26 is coupled to crossheads 30 via connecting rods 28 andpins 32. The crossheads 30 are disposed within crosshead guides 34,which generally extend from the central body 22 and facilitateconnection of the cylinders 12 to the compressor 10. In one embodiment,the compressor 10 includes two crosshead guides 34 that extend generallyperpendicularly from opposite sides of the central body or housing 22,although other configurations are also envisaged. As may be appreciated,the rotational motion of the crankshaft 26 is translated via theconnecting rods 28 to reciprocal linear motion of the crossheads 30within the crosshead guides 34.

As noted above, the cylinders 12 are configured to receive a fluid forcompression. The crossheads 32 are coupled to pistons 36 disposed withinthe cylinders 12, and the reciprocating motion of the crossheads allowscompression of fluid within the cylinders 12 via the pistons 36.Particularly, as a piston 36 is driven forward (i.e., outwardly fromcentral body 22) into a cylinder 12, the piston 36 forces fluid withinthe cylinder into a smaller volume, thereby increasing the pressure ofthe fluid. A discharge valve, such as valve assembly 20, may then opento allow the pressurized or compressed fluid to exit the cylinder 12.The piston 36 may then stroke backward, and additional fluid may enterthe cylinder 12 through a suction valve, which may also comprise a valveassembly 20, for compression in the same manner described above.Further, as will be appreciated, the cylinders 12 can be configured tofacilitate fluid compression on both the forward and the backwardstrokes of the piston 36. For instance, as the piston 36 moves forwardin the manner discussed above to compress fluid on one side of thepiston, additional fluid may be introduced into the cylinder on theopposite side of the piston. Such fluid would then be compressed on thebackward stroke of the piston 36.

FIG. 3 illustrates an example of a valve assembly 20. In thisembodiment, the valve assembly 20 includes a seat 37, a guard 38, and aplurality of poppets 39, magnets 40, coils 41, shoes 42, and springs 43.The poppets 39 are biased against openings 49 through the seat 37 by thesprings 43. The coil 41 is disposed around the poppet 39 and adjacentthe magnet 40, such that the magnet 40 passes through the coil 41 as thepoppet 39 opens and closes. The coil 41 may be disposed in a plasticbody or bushing that is recessed into an annular shelf in the guard 38.The ends of the coil 41 may connect to the phase path 21. The guideplate 38 includes a plurality of openings 44 that are in fluidcommunication with the openings 49 when the poppet opens.

In operation, a difference in fluid pressure between the opening 49 andthe opening 44 forces the poppet 39 away from the seat 37, opening thevalve 20. The poppet 39 may remain generally closed until the differencein fluid pressure exceeds a threshold, and the force of the spring 43 isovercome. Depending on the orientation of the valve 20, e.g., whether itis a suction valve or a discharge valve, fluid may flow from the opening49 to the opening 44 or vice versa. When the difference in pressuredrops below the threshold, the spring 43 drives the poppet back towardthe seat 37, closing the valve 20.

As the magnet 40 moves past the coil 41, it induces a current in thecoil 41. This current may be used for a variety of purposes, some ofwhich are described below. In some embodiments, a resistor coupled tothe phase path 21 may dissipate the electrical energy from the current,and the work that the poppet 39 performs driving the current through theresistor may dampen the movement of the poppet 39, absorbing its kineticenergy. Dampening the movement of the poppet 39 is believed to reducethe mechanical stress that the poppet 39 encounters upon impact at theends of its travel between the open and closed positions. Lowermechanical stress is believed to extend the life of the poppet 39 andlower maintenance costs.

A perspective view of another exemplary valve assembly 20 is provided inFIG. 4. In this embodiment, the valve assembly 20 includes a portion ofthe phase path 21 (though other valve assemblies 20 may include aportion of one of the other phase paths 23, 25, or 27) and a pressureplate 45 having a number of fluid ports 46, which allow a fluid, such asnatural gas, to flow through the valve assembly 20. The pressure plate45 is formed from metal, or some other suitable high-strength material.As discussed in greater detail below, the exemplary valve assembly 20also includes a plurality of poppet cage assemblies 47 (e.g., poppets ofthe type referred to as “zips”) that each generate or consume electricalenergy conveyed via the phase path 21.

Certain features of the poppet cage assemblies 47 may be betterunderstood with reference to FIGS. 5 and 6. Particularly, FIG. 5 is afront-elevation view of an embodiment of a poppet cage 48 alone, whileFIG. 6 is a front-elevation view of an embodiment of a poppet-cageassembly 47 removed from the pressure plate 45 and including a number ofcomponents disposed within the cage 48, in accordance with oneembodiment of the present invention. The cage 48 includes a mountingportion 50 and a receiving portion 52 that includes one or moreconnecting arms 54. In certain embodiments, the cage 48 is formed frommetal, although the cage 48 may be formed from other suitable materialsin other embodiments. Additionally, the cage 48 may be formed throughany suitable manufacturing process. For instance, in one embodiment, ametallic cage 48 is formed through a metal injection molding process.

The mounting portion 50, the receiving portion 52, and the connectionarms 54 generally define region 56 (e.g., an interior space) in which apoppet 58 may be disposed. In some embodiments, such as the embodimentillustrated in FIGS. 5 and 6, each cage 48 is configured to receive onlya single poppet 58 therein. In the presently illustrated embodiment, thepoppet 58 includes a central body 60 coupled to a poppet head 62. Incertain embodiments, the poppet head 62 is formed from metal through asuitable manufacturing process, such as coining, stamping, machining, orthe like. Further, in some embodiments, the central body 60 is aninjection molded plastic. It should be noted, however, that one or bothof the central body 60 and the poppet head 62 may be formed from othersuitable materials, such as ceramic, metal, or plastic, or through othersuitable manufacturing processes, other than those described above.

The exemplary poppet-cage assembly 47 also includes a seat 64 disposedwithin a bore 66 of the mounting portion 50, and an impact bushing 68disposed in a recess 70 of the receiving portion 52. As discussed ingreater detail below, during operation of the poppet-cage assembly 47,the poppet head 62 contacts the seat 64 while closing, and contactsimpact bushing 68 upon opening. The seat 64 and impact bushing 68 may beformed from the same material as each other, or from differentmaterials. In some embodiments, the one or more materials from which theimpact bushings are formed are selected based on their impact absorptionproperties. For instance, in one embodiment, the seat 64 and impactbushing 68 are made of plastic, and may be formed through an injectionmolding process or by some other suitable manufacturing process. As willbe appreciated, however, the seat 64 and impact bushing 68 may be formedfrom suitable materials other than plastic. For instance, in someembodiments, such as an embodiment including a reinforced plastic poppethead 62, it may be desirable for the seat 64 to be formed of metal.Also, in some embodiments, the one or more materials from which the seat64 or impact bushing 68 are formed has a strength or stiffness less thanthat of the poppet head 62 to reduce wear on the poppet 58 duringoperation of the valve assembly 20.

In this embodiment, the impact bushings 68 include a coil 69, asillustrated by FIG. 7. The illustrated coil 69 connects at one end tothe phase path 21 (or one of the other phase paths 23, 25, or 27) and atthe other end to a common current sink, such as ground. In otherembodiments, the phase paths 21, 23, 25, and 27 include two leads withone lead connected to each end of the coil 69. In this embodiment, thegrounded end of the coil 69 is connected to the cage 48, and the cage 48is grounded via the pressure plate 45. In other embodiments, the phasepaths 21, 23, 25, and 27 may each include two conductors, and these twoconductors may connect to each end of the coil 69. The impact bushing 68may be injection molded around the coil 69 by inserting the coil 69 in amold for the impact bushing 68 prior to injecting molding.Alternatively, or additionally, all or part of the coil 69 may bedisposed around the impact bushing 68 or other portions of thepoppet-cage assembly 47. In this embodiment, the coil 69 includes morethan 28 turns, but in other embodiments, the coil 69 may have more orfewer turns. The coil 69 is generally concentric about the central body60, and it overlaps a substantial portion or all of the travel of themagnet 80, a path that is described below by comparing FIGS. 7 and 8.That is, in this embodiment, a portion of the coil 69 is adjacent themagnet 80 both when the magnet 80 is at the top of its travel and whenthe magnet is at the bottom of its travel.

It should also be noted that while certain embodiments of the valveassembly 20 may comprise the pressure plate 45 and one or more poppetcage assemblies 47 in addition to other components, other embodiments inaccordance with the present techniques may consist of, or consistessentially of, the pressure plate 45 and the one or more poppet cageassemblies 47. Similarly, while a poppet-cage assembly 47 of someembodiments may comprise other components in addition to the cage 48,the poppet 58, the seat 64 and impact bushing 68, the coil 69, themagnets 80 and 82, or the spring 43, in other embodiments thepoppet-cage assembly 47 consists of, or consists essentially of, theseelements or some sub-combination thereof. Further, while certainembodiments of the valve assembly 20 include a plurality of poppet cageassemblies 47, it should be noted that other embodiments may insteadinclude only a single poppet-cage assembly 47 in full accordance withthe present techniques.

Additional features of an exemplary valve assembly 20 are illustrated inthe cross-section views of FIGS. 7 and 8. In the presently illustratedembodiment, the pressure plate 45 includes a recess 76 formed at an endof a fluid port 46 and is configured to receive a poppet-cage assembly47. In some embodiments, the recess 76 is concentric, or substantiallyconcentric, with the fluid port 46 to facilitate flow of a fluid fromthe fluid port 46, through the seat 64, and into the region 56 when thepoppet 58 is opened. In some embodiments, the recess 76 includes athreaded surface 74 configured to engage the threaded surface 72 of thecage 48. Other or additional attachment mechanisms, however, could beprovided in full accordance with the present techniques. For instance,in various embodiments, the pressure plate 45 may include externallythreaded extensions configured to receive internally threaded mountingportions 50 of cages 48, the cages 48 may be coupled to the pressureplate 45 via a fastener, or the like. Additionally, while the mountingportion 50 of the cage 48 is directly coupled to the pressure plate 45in certain embodiments, the mounting portion 50 of other embodiments maybe coupled to the pressure plate 45 via one or more intermediatemembers.

As will be appreciated, a poppet valve generally includes one or morebiasing components configured to apply a biasing force to the poppet 58.In the embodiment illustrated in FIGS. 7 and 8, magnets 80 and 82 aredisposed in the poppet 58 and the receiving portion 52 of the cage 48 toprovide such a biasing force. As may be seen in the presentlyillustrated embodiment, a button or washer 84 may be provided within thereceiving portion 52 of the cage 48 to prevent contact between themagnets 80 and 82. The button 84 may be formed of plastic or some othersuitable material.

In other embodiments, internal channels or grooves 94 may be formed oninterior surfaces of the cage 48 and the impact bushing 68 to allow afluid entering a lower portion of the cage 48 to escape through thegrooves 94 and a vent port 96. Still further, in one embodiment, thecentral body 60 of the poppet 58 includes one or more anti-rotationfeatures, such as fins 98, which cooperate with the channels 94 toprevent rotation of the poppet 58 within the poppet-cage assembly 47. Inalternative embodiments, the central body 60 may include otheranti-rotation features in place of, or in addition to, the fins 98. Forexample, the central body 60 may instead include one or more groovesconfigured to mate with internally protruding ribs formed on the impactbushing 68 or the cage 48.

In operation, the opposing forces on the magnets 80 and 82 generallyresult in a force on the poppet 58 toward the seat 64. Conversely, anopposing force will be applied to the poppet 58 when the pressure abovethe poppet head 62 (i.e., the region within the fluid port 46 and theimpact bushing 64) exceeds the pressure in the region 56 below thepoppet head 62. As will also be appreciated, when the biasing force isgreater than the opposing force, an upper surface 86 of the poppet head62 will generally engage a complimentary surface 88 of the seat 64 toform a seal between these two surfaces, as illustrated in FIG. 7. Upon asufficient pressure differential between the region within the seat 64and the region 56, the opposing force resulting from such pressuredifferential will exceed the biasing force applied by the magnets 80 and82 (or the spring 43), as well as any frictional forces, causing thepoppet 58 to move into the open position illustrated in FIG. 8 andallowing fluid to flow from the fluid port 46, through the seat 64, andpast the poppet-cage assembly 47. In this position, a lower surface 90of the poppet head 62 abuts a surface 92 of the impact bushing 68. Itshould be noted, however, that in other embodiments the stem or skirt ofthe central body 60 of the poppet 58 may be configured to impact thebutton 84 when the poppet 58 moves into an open position. Such contactbetween the central body 60 and the button 84 may be in addition to, orinstead of, contact between the poppet head 62 and an impact bushing 68.

As the poppet 58 moves between the closed position (FIG. 7) and the openposition (FIG. 8), the magnet 80 induces a current in the coil 69. Thecurrent arises from both the time-varying magnetic field produced by themoving magnet 80 and the position of a conductor, such as the coil 69,within the time-varying magnetic field. The coil 69 conducts thiscurrent through the portion of the phase path 21, which carries thecurrent to or from the electric device 11. The direction of the currentthrough the coil 69 changes depending on the direction that the magnet80 is moving. Thus, the current flows one direction when the poppet-cageassembly opens and the opposite direction when the poppet-cage assemblycloses. As explained below, in some embodiments, this current isrectified, filtered, and stored by the electric device 11.

Assuming the coil 69 is connected to a load, such as a resistor or aless-than-fully-charged battery, inducing the current in the coil 69establishes a force resisting movement of the magnet 80. This force isreferred to as a “Lorentz force.” The Lorentz force slows movement ofthe poppet 58 and reduces loads applied during impact with either theseat 64 or the impact bushing 68. In some systems, this effect isreferred to as “regenerative braking,” though not all embodiments areregenerative; some embodiments dissipate the electrical energy, e.g.,with a resistor, to dampen movement. The reduction in impact speed isbelieved to extend the life of the poppet 58. Further, in an embodimentdescribed below with reference to FIG. 14, the electric device 11 drivesa current through the coil 69 to accentuate this effect or to partiallyor substantially entirely control the poppet. As is explained, theelectric device 11 may sense that the poppet 58 is moving or is about tomove and drive a current through the coil 69 in a direction selected toresist movement of the coil 69. Such an actuator may by synchronizedwith the movement of the poppet 58 with information received from asensor that indicates the position of the crankshaft, and the actuatormay delay or advance the closing or opening of the poppet 58 bycounteracting or supplementing forces applied to the poppet 58 withfluid pressure.

FIG. 9 illustrates features of an embodiment of the electric device 11(or 11′). The illustrated electric device 11 includes four rectifiers100, 102, 104, and 106, four low-pass filters 108, 110, 112, and 114,and an electrical-energy storage device 116. Each of the four rectifiers100, 102, 104, and 106 is connected to one of the four low-pass filters108, 110, 112, and 114, and each of the four low-pass filters 108, 110,112, and 114 is connected to the electrical-energy storage device 116.Additionally, the four rectifiers 100, 102, 104, and 106 arerespectively connected to one of the four phase paths 21, 25, 23, and27. The phase paths 21, 25, 23, and 27, in this embodiment, connect toeither discharge valves 20 or suction valves 20′. Specifically, asexplained above, the phase paths 21 and 25 connect to discharge valves20 in groups 35 and 31, respectively, and the phase paths 23 and 27connect to suction valves 20′ in groups 33 and 29, respectively. Thedischarge valves 20 and the suction valves 20′ may both include thevalve assembly 20 illustrated by FIG. 4, but the suction valves 20′ maybe oriented in an opposite direction with respect to the direction offluid flow. In other embodiments, the suction valves 20′ may include adifferent type of valve from the discharge valves 20. In someembodiments, both valves 20 and 20′ may include other types of checkvalves (i.e., a fluid pressure actuated one-way valve).

In this embodiment, the electrical-energy storage device 116 is abattery, but in other embodiments, it may include a bank of capacitorsor other type of energy-storage device. The illustratedelectrical-energy storage device 116 connects to a device 118 thatconsumes electrical energy, such as a light, a compressor controller,compressor monitoring circuitry, the mechanical power source 16, or agrid into which power is sold.

FIG. 10 is a circuit schematic that illustrates one example of therectifier 100, the filter 108, and the electrical-energy storage device116. In this embodiment, the rectifier 100 is a full-bridge rectifierhaving four diodes. In other embodiments, the rectifier 100 may be ahalf-bridge rectifier or a switch configured to reroute current to theelectrical-energy storage device 116 based on the direction of currentflow. One terminal of the rectifier 100 is connected to the phase paths21, and the other terminal may be connected either to ground or one endof the coils 69. The other terminals of the rectifier 100, in thisembodiment, are connected to the low pass filter 108 and theelectrical-energy storage device 116. The illustrated filter 108 is alow-pass filter having a capacitor connected in parallel with theelectrical-energy storage device 116. In other embodiments, other typesof filters may be used, such as a serially connected inductor. Someembodiments may not include the filter 108, which is not to suggest thatany other feature discussed herein may not also be omitted. Theillustrated electrical-energy storage device 116 is a battery, such as anickel-metal hydride battery, a lead-acid battery, or a lithium-ionbattery.

FIG. 11 illustrates an example of the electric device 11 or 11′ thatforms a type of passive damping system. In this embodiment, each of thephase paths 21, 23, 25, and 27 couples to a resistor. Movement in eachof the valves 20 or 20′ induces current in the phase paths 21, 23, 25,and 27, and this current is dissipated by the resistors. Thus, thekinetic energy of components in the valves 20 and 20′ may be convertedto electrical energy in the phase paths and then to heat energy in theresistors. In some embodiments, active or passive cooling may dissipatethis heat energy.

FIG. 12 illustrates an example of an energy-scavenging process 120. Theillustrated process begins with causing relative movement of magnet anda conductor by moving a valve member, as illustrated by block 122. Thevalve member may be any of a variety of types of valve members,including a ball in a ball valve, a flap in a butterfly valve, themoving portion of a check valve (e.g., a poppet head), a ring in amoppet, or the like. Moving the valve member may include moving thevalve member as a result of a change in fluid pressure across the valvemember. For example, in some of the previously described embodiments,opening a discharge valve includes increasing a fluid pressure (thoughopening the discharge valve may result in a decrease in fluid pressureafter it is open), and opening a suction valve includes decreasing afluid pressure.

Next in the process 120, a current is induced in the conductor, asillustrated by block 124. In some embodiments, the conductor is a coil,and the magnet is moved partially or entirely through the coil. Themagnet may be directly or indirectly connected to the valve member. Forexample, the magnet may be affixed to the valve member, or the magnetmay be coupled to the valve member by a mechanical linkage, such as alever. In some embodiments, multiple magnets are coupled to the valvemember, and each of the magnets is moved through a coil. The movement ofthe magnet may take a variety of forms. For instance, the magnet maytwist, translate generally linearly, follow a generally curved path,orbit an axis, or a combination thereof.

Finally, in this embodiment, the electrical energy from the current isstored, as illustrated by block 126. Storing the electrical energy mayinclude charging a battery or a capacitor. Storing may also includechanging the form of the electrical energy from alternating current todirect current by rectifying and filtering the current. In otherembodiments, the electrical energy is consumed immediately.

FIG. 13 illustrates another example of the electric device 11 (or 11′).In this embodiment, the electric device 11 is an actuation system thatincludes drivers 128, 130, 132, and 134, and a controller 136. Each ofthe drivers 128, 130, 132, and 134 has an output connected to one of thephase paths 21, 25, 23, and 27, respectively. The drivers 128, 130, 132,and 134 are configured to assert a voltage on the phase paths 21, 23,25, and 27 in response to a signal from the controller 136. Accordingly,an input of each of the drivers 128, 130, 132, and 134 is also connectedto the controller 136.

In this embodiment, the controller 136 is connected to a position sensor138. The illustrated position sensor 138 is a device configured toindicate generally when the valves 20 and 20′ are going to open or closeor are opening and closing. In some embodiments, the position sensor 138may indicate the position of the mechanical driver 16, the crankshaft26, or the pistons 36, or the position sensor 138 may indicate somemeasure of the pressure within the cylinders 12. In certain embodiments,the position sensor 138, like other components discussed herein, may beomitted, and the controller 136 may sense the movement of the valves 20or 20′ by monitoring voltages of, or currents induced on, the phasepaths 21, 23, 25, and 27.

In operation, the electric device 11 executes an exemplaryenergy-scavenging process 140 illustrated by FIG. 14. Theenergy-scavenging process 140 includes determining whether a valvemember is being moved by a fluid pressure, as illustrated by block 142.Determining whether a valve member is being moved by a fluid pressuremay include monitoring the fluid pressure, monitoring the position of acomponent that affects the fluid pressure, or directly monitoring theposition or velocity of the valve member.

If the valve member is being moved, its movement is resisted by drivinga current through a coil adjacent a magnet coupled to the valve member,as illustrated by block 144. The current establishes a Lorentz-forceconfigured to resist movement. As such, the Lorentz-force may becharacterized as a vector with a component in a direction that isgenerally opposite the direction in which the magnet is moving. In someembodiments, the Lorentz-force vector, rather than just a component ofthe vector, is generally opposite the direction in which the magnet ismoving. This force slows the valve member, thereby reducing forcesapplied to and by the valve member upon impact. In this embodiment, acurrent is driven through the coil both when the valve member is openingand when it is closing, but in other embodiments, only one of thesemovements may be slowed by driving a current through the coil.

In some embodiments, the electric device 11 adjusts the thresholdpressure of the valves 20 and 20′. The threshold pressure is the fluidpressure at which the valves 20 or 20′ change state, e.g. open or close.In these embodiments, the controller 136 signals the drivers 128, 130,132, and 134 to drive a current through the coils 69 before the valves20 or 20′ change state. Depending on whether the threshold pressure isbeing increased or decreased, the direction of the current is selectedto either hold the valve 20 or 20′ in its current state, therebyincreasing the threshold pressure, or drive the valve from its currentstate, thereby lowering threat the threshold pressure. This may adjustthe capacity of the compressor 10 (FIG. 1). The magnitude of the currentmay be increased or decreased based on the desired change in thethreshold pressure.

Other embodiments may use other configurations of valves, such as thepoppet assembly 47′ illustrated by FIG. 15. In this embodiment, thepoppet head 62 is biased toward the pressure plate 45 by a spring 145.The illustrated spring 145 presses against the magnet 80. In someembodiments, e.g., those with a spring, the magnet 80 may be coupled tothe poppet cage 48, and the coil 69 may be coupled the poppet head 62.In this arrangement, the magnet 80 may remain generally static, whilethe coil 69 moves with the poppet head 62.

FIGS. 16 and 17 illustrate another embodiment of a poppet assembly 47.In this example, the poppet assembly 47 includes a cage 148, a coil 150,a poppet 152, a spring 154, and a magnet 156. The spring 154 biases thepoppet 152 toward the cage 148, and the magnet 156 is coupled to distalend of the poppet 152. The coil 150 is disposed about the cage 148 nearthe magnet 156. As the poppet is drawn downward by a difference in fluidpressure, the magnet 156 is moved relative to the coil 150, therebycreating an electric current. The poppet 47 may be used in one of thesuction valves described above.

While the invention may be susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the invention is not intended tobe limited to the particular forms disclosed. Rather, the invention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the followingappended claims.

The invention claimed is:
 1. A compressor, comprising: a piston; and avalve assembly, comprising: a check valve comprising a valve member,wherein the check valve is configured to change state in response to achange in fluid pressure; a magnet coupled to the valve member; animpact bushing, wherein the impact bushing is configured to dampen animpact of the valve member; and an electrical conductor near the magnet,wherein the electrical conductor is imbedded within the impact bushingand configured to convert a time-varying magnetic field into a currentas the magnet moves past at least a portion of the electrical conductor.2. The compressor of claim 1, wherein the valve member comprises apoppet head.
 3. The compressor of claim 1, wherein the check valvecomprises a cage that receives the valve member, the magnet, and theelectrical conductor.
 4. The compressor of claim 1, wherein at least aportion of the conductor is disposed around at least a portion of themagnet.
 5. The compressor of claim 4, wherein the conductor comprises acoil disposed about at least a portion of a path of travel of themagnet.
 6. The compressor of claim 1, comprising electric device coupledto the electrical conductor.
 7. The compressor of claim 6, wherein theelectric device comprises an electrical energy storage device and arectifier.
 8. The compressor of claim 1, comprising: a driver with anoutput coupled to the electrical conductor; and a controller coupled toan input of the driver.
 9. The compressor of claim 1, wherein the magnetcomprises a permanent magnet.
 10. The compressor of claim 1, wherein theelectrical conductor comprises a coil, and wherein the coil isconfigured to allow the magnet to move axially around or through thecoil.
 11. The compressor of claim 1, wherein the valve assembly is apoppet valve assembly.
 12. The compressor of claim 1, comprising acontroller or monitoring circuitry configured to receive the currentgenerated in the electrical conductor.